A jet engine includes a shaft functioning as a principal axis that transmits rotating power generated by a turbine to a compressor or the like. In the jet engine, these may be a case where the shaft is made to be hollow and a center vent tube is provided inside the shaft. In the center vent tube, a distal end portion of the center vent tube is fixed to the shaft, and the center vent tube is rotated with the shaft and discharges a lubricant used at a bearing or the like from a lubricant closure to the outside.
The thermal deformation amount of the center vent tube and the thermal deformation amount of the shaft are different from each other due to a difference in materials and shapes thereof. Therefore, if the center vent tube is rigidly fixed to the shaft at multiple locations in an axial direction of the shaft, large stress is locally generated at the multiple fixed locations due to thermal deformation. Furthermore, the center vent tube is twisted when the center tube is rotated along with the shaft. In this case as well, large stress is locally generated at the multiple fixed locations. Accordingly, in general only the distal end of the center vent tube is rigidly fixed to the shaft and the number of fixed locations between the center vent tube and the shaft is reduced as much as possible. However, since the center vent tube is an elongated member, positional regulation of the center cent tube inside the shaft cannot be performed in a case where on only the distal end of the center vent tube is fixed. Accordingly, an aligning device, which aligns the center vent tube by slidably supporting the center vent tube with respect to one location or multiple locations in the axial direction of the shaft, is provided (refer to Patent Document 1).
The aligning device includes a cylindrical sleeve (a ring 50 in Patent Document 1) which surrounds the center vent tube and a support ring (a ring 62 in Patent Document 2) which is inserted between the sleeve and the shaft and which supports the sleeve. The aligning device slidably supports the center vent tube by making a resin ring, which is disposed between an inner circumferential surface of the sleeve and an outer circumferential surface of the center vent tube, about the center vent tube.
As shown in Patent Document 1, a portion of an outer circumferential surface of the sleeve is made to be a tapered surface. The support ring is pushed out and enlarged from inside in a radial direction thereof to outside in the radial direction thereof by the tapered surface of the sleeve. With the support ring being pushed out and enlarged, a reaction force the support ring receives from an inner circumferential surface of the shaft becomes a force (retention force) which retains the sleeve. Accordingly, the sleeve is supported. Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5 disclose related techniques.